In the construction of machinery, it is sometimes desirable to provide biasing means for exerting a first reaction force against an element and, after a preselected amount of movement, exert a second greater reaction force against the element. Under certain dirty environments and biasing requirements, a plurality of compressible helical springs actuated by a piston malfunction and/or do not provide the preselected, desired biasing forces. The apparatus of this invention is provided to solve this problem.
One use that is expected to be made of the apparatus of this invention is to controllably dampen the contacting forces between a sprocket wheel and a track of a continuous track of a crawler-type vehicle and thereby suppress emitted noise and reduce wear. A biasing means which will perform some of the functions of the apparatus of this invention is shown in U.S. Pat. No. 3,889,550, which issued to Roger L. Boggs et al on June 17, 1975, from an application filed on Nov. 19, 1973, and which is assigned to the assignee of the subject invention.
This invention therefore resides in a biasing element having a housing having resilient walls, an axis, first and second end portions, and a chamber. A force transmitting material is positioned within the chamber between a retaining means and a piston. The piston is movable between a first position at which the piston is in contact with the force transmitting material and a second position at which the force transmitting material is moved by the piston into forcible contact with resilient walls of the housing and said housing walls are deflected in response to said forcible contact by said force transmitting material.